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ucmb: Fix the lowlevel protocol

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SVN-Revision: 14549
This commit is contained in:
Michael Büsch 2009-02-18 11:54:09 +00:00
parent 87a2d3888c
commit 1328bf9395
5 changed files with 100 additions and 29 deletions
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5
package/ucmb/Makefile
View File

@ -12,9 +12,10 @@ PKG_RELEASE:=1
include $(INCLUDE_DIR)/package.mk
define KernelPackage/ucmb
SUBMENU:=Other modules
DEPENDS:=@LINUX_2_6 +kmod-spi-gpio
DEPENDS:=@LINUX_2_6 +kmod-spi-gpio +kmod-crc16
KCONFIG:=CONFIG_SPI=y \
CONFIG_SPI_MASTER=y
TITLE:=Microcontroller Message Bus (EXPERIMENTAL)
@ -24,7 +25,7 @@ endef
define Build/Prepare
mkdir -p $(PKG_BUILD_DIR)
$(CP) ./src/* $(PKG_BUILD_DIR)/
$(CP) ./driver/* $(PKG_BUILD_DIR)/
endef
define Build/Compile

0
package/ucmb/src/Makefile → package/ucmb/driver/Makefile
View File

72
package/ucmb/src/ucmb.c → package/ucmb/driver/ucmb.c
View File

@ -17,10 +17,13 @@
#include <linux/spi/spi_bitbang.h>
#include <linux/gfp.h>
#include <linux/delay.h>
#include <linux/crc16.h>
#define PFX "ucmb: "
#define DEBUG
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Microcontroller Message Bus");
@ -28,6 +31,8 @@ MODULE_AUTHOR("Michael Buesch");
struct ucmb {
unsigned int msg_delay_ms;
/* Misc character device driver */
struct miscdevice mdev;
struct file_operations mdev_fops;
@ -45,6 +50,10 @@ struct ucmb_message_hdr {
__le16 len; /* Payload length (excluding header) */
} __attribute__((packed));
struct ucmb_message_footer {
__le16 crc; /* CRC of the header + payload. */
} __attribute__((packed));
struct ucmb_status {
__le16 magic; /* UCMB_MAGIC */
__le16 code; /* enum ucmb_status_code */
@ -58,6 +67,7 @@ enum ucmb_status_code {
UCMB_STAT_EPROTO, /* Protocol format error */
UCMB_STAT_ENOMEM, /* Out of memory */
UCMB_STAT_E2BIG, /* Message too big */
UCMB_STAT_ECRC, /* CRC error */
};
@ -71,6 +81,9 @@ static struct ucmb_platform_data ucmb_list[] = {
.gpio_sck = 0,
.gpio_miso = 1,
.gpio_mosi = 2,
.mode = SPI_MODE_0,
.max_speed_hz = 128000, /* Hz */
.msg_delay_ms = 1, /* mS */
},
};
@ -106,6 +119,8 @@ static int ucmb_status_code_to_errno(enum ucmb_status_code code)
return -ENOMEM;
case UCMB_STAT_E2BIG:
return -E2BIG;
case UCMB_STAT_ECRC:
return -EBADMSG;
}
return -EBUSY;
}
@ -115,7 +130,6 @@ static inline struct ucmb * filp_to_ucmb(struct file *filp)
return container_of(filp->f_op, struct ucmb, mdev_fops);
}
/* FIXME offp */
static ssize_t ucmb_read(struct file *filp, char __user *user_buf,
size_t size, loff_t *offp)
{
@ -123,13 +137,11 @@ static ssize_t ucmb_read(struct file *filp, char __user *user_buf,
u8 *buf;
int res, err;
struct ucmb_message_hdr hdr;
struct ucmb_message_footer footer;
struct ucmb_status status = { .magic = cpu_to_le16(UCMB_MAGIC), };
u16 crc = 0xFFFF;
err = -E2BIG;
if (size > PAGE_SIZE)
goto out;
if (size > UCMB_MAX_MSG_LEN)
goto out;
size = min_t(size_t, size, PAGE_SIZE);
err = -ENOMEM;
buf = (char *)__get_free_page(GFP_KERNEL);
@ -139,6 +151,10 @@ static ssize_t ucmb_read(struct file *filp, char __user *user_buf,
err = spi_read(ucmb->sdev, (u8 *)&hdr, sizeof(hdr));
if (err)
goto out_free;
#ifdef DEBUG
printk(KERN_DEBUG PFX "Received message header 0x%04X 0x%04X\n",
le16_to_cpu(hdr.magic), le16_to_cpu(hdr.len));
#endif
err = -EPROTO;
if (hdr.magic != cpu_to_le16(UCMB_MAGIC))
goto out_free;
@ -147,17 +163,31 @@ static ssize_t ucmb_read(struct file *filp, char __user *user_buf,
goto out_free;
size = le16_to_cpu(hdr.len);
err = spi_read(ucmb->sdev, buf, size);
if (err)
goto out_free;
err = spi_read(ucmb->sdev, (u8 *)&footer, sizeof(footer));
if (err)
goto out_free;
err = -EFAULT;
if (copy_to_user(user_buf, buf, size))
crc = crc16(crc, &hdr, sizeof(hdr));
crc = crc16(crc, buf, size);
crc ^= 0xFFFF;
if (crc != le16_to_cpu(footer.crc)) {
err = -EPROTO;
status.code = UCMB_STAT_ECRC;
goto out_send_status;
}
if (copy_to_user(user_buf, buf, size)) {
err = -EFAULT;
status.code = UCMB_STAT_ENOMEM;
goto out_send_status;
}
status.code = UCMB_STAT_OK;
err = 0;
out_send_status:
status.code = err ? UCMB_STAT_ENOMEM : UCMB_STAT_OK;
res = spi_write(ucmb->sdev, (u8 *)&status, sizeof(status));
if (res && !err)
err = res;
@ -167,7 +197,6 @@ out:
return err ? err : size;
}
/* FIXME offp */
static ssize_t ucmb_write(struct file *filp, const char __user *user_buf,
size_t size, loff_t *offp)
{
@ -175,8 +204,10 @@ static ssize_t ucmb_write(struct file *filp, const char __user *user_buf,
u8 *buf;
int err;
struct ucmb_message_hdr hdr = { .magic = cpu_to_le16(UCMB_MAGIC), };
struct ucmb_message_footer footer = { .crc = 0xFFFF, };
struct ucmb_status status;
struct spi_transfer spi_hdr_xfer;
struct spi_transfer spi_footer_xfer;
struct spi_transfer spi_data_xfer;
struct spi_message spi_msg;
@ -192,6 +223,10 @@ static ssize_t ucmb_write(struct file *filp, const char __user *user_buf,
goto out_free;
hdr.len = cpu_to_le16(size);
footer.crc = crc16(footer.crc, &hdr, sizeof(hdr));
footer.crc = crc16(footer.crc, buf, size);
footer.crc ^= 0xFFFF;
spi_message_init(&spi_msg);
memset(&spi_hdr_xfer, 0, sizeof(spi_hdr_xfer));
@ -204,18 +239,28 @@ static ssize_t ucmb_write(struct file *filp, const char __user *user_buf,
spi_data_xfer.len = size;
spi_message_add_tail(&spi_data_xfer, &spi_msg);
memset(&spi_footer_xfer, 0, sizeof(spi_footer_xfer));
spi_footer_xfer.tx_buf = &footer;
spi_footer_xfer.len = sizeof(footer);
spi_message_add_tail(&spi_footer_xfer, &spi_msg);
/* Send the message, including header. */
err = spi_sync(ucmb->sdev, &spi_msg);
if (err)
goto out_free;
/* The microcontroller deserves some time to process the message. */
msleep(1);
if (ucmb->msg_delay_ms)
msleep(ucmb->msg_delay_ms);
/* Get the status code. */
err = spi_read(ucmb->sdev, (u8 *)&status, sizeof(status));
if (err)
goto out_free;
#ifdef DEBUG
printk(KERN_DEBUG PFX "Sent message. Status report: 0x%04X 0x%04X\n",
le16_to_cpu(status.magic), le16_to_cpu(status.code));
#endif
err = -EPROTO;
if (status.magic != cpu_to_le16(UCMB_MAGIC))
goto out_free;
@ -244,6 +289,7 @@ static int __devinit ucmb_probe(struct platform_device *pdev)
ucmb = kzalloc(sizeof(struct ucmb), GFP_KERNEL);
if (!ucmb)
return -ENOMEM;
ucmb->msg_delay_ms = pdata->msg_delay_ms;
/* Create the SPI GPIO bus master. */
@ -280,9 +326,9 @@ static int __devinit ucmb_probe(struct platform_device *pdev)
printk(KERN_ERR PFX "Failed to allocate SPI device\n");
goto err_unreg_spi_gpio_pdev;
}
ucmb->sdev->max_speed_hz = 500000;
ucmb->sdev->max_speed_hz = pdata->max_speed_hz;
ucmb->sdev->chip_select = 0;
ucmb->sdev->mode = SPI_MODE_0;
ucmb->sdev->mode = pdata->mode;
strlcpy(ucmb->sdev->modalias, "ucmb", /* We are the SPI driver. */
sizeof(ucmb->sdev->modalias));
ucmb->sdev->controller_data = (void *)pdata->gpio_cs;

38
package/ucmb/driver/ucmb.h Normal file
View File

@ -0,0 +1,38 @@
#ifndef LINUX_UCMB_H_
#define LINUX_UCMB_H_
#include <linux/types.h>
/**
* struct ucmb_platform_data - UCMB device descriptor
*
* @name: The name of the device. This will also be the name of
* the misc char device.
*
* @gpio_cs: The chipselect GPIO pin. Can be SPI_GPIO_NO_CHIPSELECT.
* @gpio_sck: The clock GPIO pin.
* @gpio_miso: The master-in slave-out GPIO pin.
* @gpio_mosi: The master-out slave-in GPIO pin.
*
* @mode: The SPI bus mode. SPI_MODE_*
* @max_speed_hz: The bus speed, in Hz. If zero the speed is not limited.
* @msg_delay_ms: The message delay time, in milliseconds.
* This is the time the microcontroller takes to process
* one message.
*/
struct ucmb_platform_data {
const char *name;
unsigned long gpio_cs;
unsigned int gpio_sck;
unsigned int gpio_miso;
unsigned int gpio_mosi;
u8 mode;
u32 max_speed_hz;
unsigned int msg_delay_ms;
struct platform_device *pdev; /* internal */
};
#endif /* LINUX_UCMB_H_ */

14
package/ucmb/src/ucmb.h
View File

@ -1,14 +0,0 @@
#ifndef LINUX_UCMB_H_
#define LINUX_UCMB_H_
struct ucmb_platform_data {
const char *name;
unsigned long gpio_cs;
unsigned int gpio_sck;
unsigned int gpio_miso;
unsigned int gpio_mosi;
struct platform_device *pdev; /* internal */
};
#endif /* LINUX_UCMB_H_ */